This invention relates generally to the abatement of contaminant laden industrial process emissions and more specifically, to a ducting, valving and purging system that directs and controls the flow of such emissions to and through a two chamber regenerative oxidizer.
Industrial process emissions often contain combustible contaminants and/or odors that, if released to atmosphere, have the potential of polluting the environment. Thermal and/or catalytic oxidizers increase the temperature of such process emissions to a temperature above the ignition temperature of the contaminants therein so as to oxidize the contaminants. Characteristically, power actuated, computer controlled flow control valves, of the type disclosed in U.S. Pat. No. 5,000,422 or U.S. Pat. No. 5,327,928, both of which are assigned to the assignee of the present invention, are used to direct the emissions to one or more oxidizers.
One problem that materially effects the efficiency of such oxidizers is short circuiting of the oxidizer by contaminated emissions incident to opening and closing of the valves required for control of fluid flow to and from the regenerators. Obviously, short circuiting of emissions between flow control valves in the partially open condition seriously compromises the efficiency of the oxidizer.
Another problem relates to purging of the regenerative chambers without inducing wide pressure fluctuations. Purging of the regenerative chambers is required to remove nonoxidized source emissions from the open volumes within, for example, the ceramic media.
More specifically, as the regenerative chambers of known two chamber regenerative oxidizers switch from inflow to outflow, there is both a momentary change in system pressure due to simultaneous opening and closing of all valves, and a momentary period where incoming contaminant laden emissions short circuit the common oxidation chamber. Pressure variations place excessive loads on the fluid moving equipment and are unacceptable in processes being controlled via the regenerative oxidizer. Short circuiting of the oxidation chamber compromises efficiency of the system.